Generally, dispensing equipment falls broadly into three categories: first, the typical finger operated pump sprayer; next, the various versions of pump sprayers that are manually operated by means of a trigger or handle, or the squeeze bottle type; and lastly, the broad field of pressurized containers commonly referred to as "aerosol bombs". This latter group depends entirely upon a gas propellant, usually one of the halogenated hydrocarbons, especially the flurocarbons. This propellant is a liquid at a low temperature and/or high pressure but it boils rapidly at ordinary room temperatures and pressures, creating tremendous volumes of gas to dispense many commonly used products. Although aerosol bomb type dispensers are in wide-spread commercial use, they inherently possess at least several undesirable and potentially dangerous characteristics. The Medical Profession has already documented the serious health hazards associated with the inhalation of the propellant vapors. The dispenser is potentially explosive at elevated temperatures which create explosively high propellant pressures within the container. In fact, certain laws require that warnings be placed on the container cautioning the user of the aerosol bomb from exposing the container to elevated temperatures and warning against the danger of puncturing the container. Other associated problems, such as the need for metal containers due to the high pressures involved, cause additional disadvantages, i.e., the silent danger of electrolysis and corrosion, along with potential contamination of product to be dispensed by the gas propellant. Furthermore, aerosol bombs are not reuseable and pose a serious ecological problem caused by the daily disposition of astronomical quantities of empty aerosol containers. On the other hand, all manually or finger-operated pump sprayers depend entirely on the human effort, resulting in variable spray quantities in direct proportion to the physical capabilities of the operator. Many of these spray devices dribble, deliver coarse, wet and/or excessive quantities, oftimes leak, fail to operate and, generally, are not too dependable. Various types of pressurized liquid dispensers incorporating manual pumping and dispensing means have been provided. The devices are typically used for dispensing beverages and generally are quite complicated and cumbersome, and not at all suited for the same applications as an aerosol bomb type dispenser.
The novel low-pressure dispensing apparatus of the present invention provides a much needed alternative to the aerosol bomb type of dispenser with its inherent dangers, caused by its vapors and explosive qualities, and to finger operated pump sprayers and trigger or handle operated sprayers with their attendant deficiencies.
Among the principal objects of the present invention are to provide a dispenser for materials such as liquids (as an aerosol or as a liquid jet), foams and powders, which is reuseable, easy to use, foolproof in operation, can use ordinary air as propellant, presents a minimum health hazard, is not as subject to harmful explosion or leakage as high pressure dispensers, is competitively priced and will dispense most materials as well as or better than an aerosol bomb without the aforementioned perils and hazards associated with this latter type. With the present invention the container can be entirely plastic; this affords even further advantages and benefits. Not only is plastic relatively inert and non contaminating, but its use permits molding much of the structure of the dispensing apparatus integrally with the container itself, thereby eliminating many individual parts and the assembly thereof into the container. Most of the separate operating parts of the dispenser can also be made of plastic. Accordingly, the construction of the dispensing apparatus of the present invention is especially economical and well adapted for mass-production techniques. Furthermore, the apparatus can be refilled and reused a number of times.
The invention also possesses novel operating features heretofore not attained in dispensing apparatus of this type. The container can be pressurized to any desired pressure up to a preset maximum which cannot be exceeded; the container can be de-pressurized at any time without dispensing any product from the container; and the pumping mechanism for pressurizing the container can be compactly stored and sealed in relation to the container and includes a conveniently grippable operating handle.
The foregoing features along with additional advantages and benefits of the invention will be seen in the ensuing description and claims which are to be taken in conjunction with the accompanying drawings.